Hole chamfering tool



July 12, 1960 H. w. EBERHARDT HOLE CHAMF'ERING, TOOL Filed Dec. 1. 1958VIII/III! INVENTOR HERMAN w. LBERHARDT Hli ATTORNEY .1 Home Term.Herman"WJ"EberharilhlFitirlawnfNl, as'signor. toCurtiss-Wright'Gorporaition, -a" corporation of Delaware :Filed Bee; 1, 1958;Ser.No.7775291 Claims. or; 772 3.5;

-My -invention*r'elateszto a holech'amfering tobl and- 'is particularlydirected tome'ans'forchamfe'ring a'hole with a hidden j e'dgei'?'Whenboth sidesof a' workpiece are accessible,:holes through the partare easily chamfered with conventional,

chamfering tools. -If,4however,..one.side of,rthe workpieceis"'inacces'ible,as 'for example,""in closed or sub-, stantially closedshapes, aspecialtool "is required to .chamferathe .hidden edge.of .the:hole, that? ion the inaccessible .side .of .the:=piece. wl'speciali.Itools .em- :ployed heretofore. .for this..purpose shave not:I-been.too

satisfactory either in operation or in results obtained.

theeiedge One of the diflicultiesencounterediirtchamfering a hid- -xlenedge.rof' a; h ole;is thatgthe -operation-zcannot be observed and inconsequence the depth of cut is not readily controlled.

The prime object of this invention is to provide a generally improvedtool forchamfering the hidden edge" of a hole and to provide for acontrolled depth of cut I on a hidden edge with such a tool.

Other objects and advantages of the invention will become apparenthereinafter.

The invention is explained in detailin the ensuing description, whichshould be read in conjunction with the annexed drawing in which similarreference char acters designate similar parts and in which: I

" Fig. 1 is a top plan view, and Fig. 2 is an elevational view,partially in section, showing the tool of the invention;

Figs. 3 and 4 are top and elevational views respectively of acylindrical member constituting the tool body;

Figs. 5 and 6 are elevational views of portions of the tool movablewithin the cylindrical member of Figs. 3 and 4;

Fig. 7 is a top plan view of a wedge used in conjunction with the toolof the invention; 7

Fig. 8 is a side elevational view of the wedge of Fig. 7; I

Fig. 9 is an enlarged elevational view illustrating the cutting portionof the tool.

Referring to the drawings, reference character 1 designates the tool ofthe invention. Such tool includes a cylindrical body member 2 whichhouses a two-part member 3. The two-part member 3 comprises an uppercylindrical portion 4, having a sliding fit with member 2, and a lowercylindrical portion 5 of lesser diameter than the portion 4. A spring 6within the member 2 abuts at opposite ends against member 2 and portion4 of the member 3. The purpose of the spring 6 in carrying out thefunction of the tool will be explained hereinafter.

As shown, portion 4 of the two-part member 3 is tapped at 7 to receive ascrew 8. The body member 2 is provided with an L-shaped slot 9, and thescrew 8 registers a the hole.

2,944,447, p tent d July 12, 19

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7 :2 '7 slot"'9. Whenthetool' is' being rea'diedfor use. or'for.withdrawall-from a holeupon completion of, a chamfer- 'ing operatiomthescrew 8 -is positioned in the horizontal portion 11 ofthe slot'9 and.caused to lock in placein "the end'12' of slot portion 11. Thescrew ispositioned bydepressing the-knob 13 formed on the upper end of portion 4of the two-partmember 3 to compress'the spring'6. With the screw at thelower end of'the vertical ,portionltl of the slot'9 the knob 13 isturned slightly in] acounterclockwise direction to lock the screw insmaller'diametefthan portion 4. .The portion 5 carries a hook-shapedworking part of the tool 14 at its lower end. 'fTlie two parts,'4 and.5, .are separable, being joined by a screw connection at 15. If,replacement of the working part becomes necessary due .to.darnage or ifa different 3 working part is required for any other reason the; lowerportion 5 .of two-part member 3 may be separated from 3 upper portion'4. and withdrawn 'from the housing .2, through ope'ning15' at thelowerendofthe housingand .;the .part.5 replaced. Portion 4 of'thetwo-part member remains Jwithin Ithe cylindrical. member. 2. A

. 'As. stated,-.' the tool'jis readied foruseqby. lockingthe -screw. 8'.in portiorL'lZ of the slot 9,1thereby. disposing the ...two;partQmember. and..the, .cutting. portion 14. of. the .tool intheir' lowestpositions relative to the member 2. When the screw has been so located,the working part 14 of the tool protrudes a considerable distance belowthe extreme end of member 2 and can be inserted through a hole forchamfering the hidden edge. Because of the configuration of the workingpart 14, such part must be manipulated into the hole by first insertingthe extreme end offpart 14.,into the hole with the axis of the tool atan acute angle to the surface of the workpiece, and then moving the toolinto a vertical position to complete the insertion.

, After insertion of the cutting portion of the tool into a hole as 16(Fig. 9) a wedge 17 is inserted between the lower end 18 of cylindricalmember 2 and the-workpiece 19, the wedge being recessed at 17' to fitabout portion 5 of two-part member 3. The knob 13 of the member 3 isthen slightly depressed and turned to release the member 3 from itslocked condition. The spring 6 becomes effective to urge the member 3upwardly in cylindrical member 2 and force the cutting edge 20 of thetool against the edge 21 of the hole. The spring 6 urges the lower end18 of cylindrical member 2 against the upper surface of the wedge. Theknob 13 of the tool is then turned so as to rotate the tool and causethe cutting edge 20 to chamfer the edge 21 of Knob 13 is preferablyknurled as at 13 to facilitate the turning of the tool with the fingers.Preferably the diameter of the working portion 14 of the tool is onlyslightly less than the diameter of the hole. The cutting portion 14 ofthe tool is formed with an abutment shown as a flat surface at 22. Thissurface of the workpiece and prevents further cutting of the metal. Thecutting portion 14 of the tool may be designed with an abutting surface22 to provide any depth of cut and different parts may be substitutedfor portion 5 as required to obtain a different depth of'c'ut, the

with and protrudes into this slot in the assembled tool. When the toolis in use theiscrew 8 is disposed in some 22 in relation to cutting edge2 p v V 1 intermediate position in the vertical portion 10 of the Afterthe edge 21 of the hole has been chamfered,

depth of cut being determined by the position of surface 'knob 13 isdepressed and turned to lock the screw 8 in The wedge'17 is thenWithdrawn tion of the device is, for example, extremely simple and theparts are easily assembled. Also the working portion of the tool iseasily removed and replaced when necessary. In addition, a controlleddepth of cut. is provided for even though the actual cutting during achamfering operation is not directly observable by one using the tool.

While only one form of the invention has been shown 7 in the drawingsand described in the specification, it will be obvious to those skilledin the art that various changes and modifications may be made instructure without departing from the spirit and scope of the inventionas set out in the appended claims.

I claim: 1. A hole chamfering device'comprising a tool portion with acutting edge for 'chamfering the inside edge of v the hole of aworkpiece, a pair of members one of which urging the cutting edgeagainst the inside edge of the hole and the said other member againstsaid support, and means for turning the tool portion to accomplish thechamfering of the hole.

2. The combination as defined in claim 1 including locking means forholding the said one member in a fixed position against the biasingforce of the spring means.

3. A hole chamfering device comprising a tool portion with a cuttingedge for chamfering the inside edge of the hole of a workpiece, a pairof'members one of which is attached to said tool portion and is axiallymovable relative to the other member, a support for the other memberhaving a substantially -U-shaped end portion insertable between theother said member and the workpiece and being substantially wedge shapedin a plane perpendicular to the plane of the U-shaped portion,

.spring means which bears against said members urging the cutting edgeagainst the inside edge of the hole and the said other member againstsaid support, and means for turning the tool portion to accomplish thechamfering is attached to said tool portion and is axially movable,relative to the other member, a support for the said other member havinga substantially U-shaped portion insertable between the said othermember and the workpiece, spring means which bears against said membersof the. hole.

References Cited in the file ofthis patent UNITED STATES PATENTS 308,842Hunt Dec. 2, 1884 2,188,624 Dantry et a1. Jan. 30, 1940 2,365,648Rossmann Dec. 19, '1944 FOREIGN PATENTS 7 658,867 Great Britain Oct. 17,1951

